Why does CAS 25956-17-6 appear in more than one EU cosmetic annex?

A substance identified by CAS 25956-17-6 may appear in multiple EU cosmetic regulation annexes when it is subject to different conditions in different contexts — for example, restricted under Annex III with specific conditions, while also appearing in Annex IV as an approved colorant under separate entry conditions. Each entry must be reviewed individually.

How do I check if my formula contains a substance with CAS 25956-17-6?

Use the INCI Checker on CosIng Checker with INCI names, CAS numbers or EC numbers. Paste CAS 25956-17-6 to screen it directly, then review every linked annex record and supplier document.

CAS 2 records

CAS 25956-17-6

Q: How do I use CAS 25956-17-6 for compliance screening?

Cross-reference CAS 25956-17-6 against your raw material specification sheets and CoA documents. When it appears in Annex II, verify absence. When it appears in Annex III, verify that concentration limits and product type conditions are met. All annex entries sharing this CAS number are listed on this page.

CAS 25956-17-6 matches 2 EU annex records across Annex II–VI of Regulation 1223/2009.

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Chemical identity and properties

PubChem 2D chemical structure for CAS 25956-17-6

CAS 25956-17-6PubChem CID 33258

E129

Allura red AC is a naphthalenesulfonic acid. — ChEBI

IUPAC name: disodium;6-hydroxy-5-[(2-methoxy-5-methyl-4-sulfonatophenyl)diazenyl]naphthalene-2-sulfonate

Molecular formula: C18H14N2Na2O8S2
Molecular weight: 496.4 g/mol
Exact mass: 495.99869632 Da
Topological polar surface area: 185.0 Å²
Hydrogen-bond donors: 1
Hydrogen-bond acceptors: 10
Covalent units: 3
Defined stereocentres: 0

Also known as

RefChem:1084024Allura Red ACAllura RedAllura red AC dyeFood red 17Fancy RedFood Red No. 40C.I. Food Red 17

16 more reported names

FD&C Red No. 40Allura Red 40Japan Red 40Curry redALLURA RED C.I.16035Japan Food Red No. 40CI 16035FDC Red 40 dyeHSDB 7260Red 40WZB9127XOARed No. 40FD and C Red No. 40Allura Red AC (E 129)Disodium 6-hydroxy-5-((6-methoxy-4-sulfo-m-tolyl)azo)-2-naphthalenesulfonateFD & C Red no. 40

Open full PubChem record PubChem annotations 3D structure image

External database identifiers

ChEBI:CHEBI:172687
ChEMBL:CHEMBL174821
ChEMBL:CHEMBL3188816
EPA DTXSID:DTXSID4024436
EPA DTXSID:DTXSID70860355

Retrieved from NIH PubChem on 2026-09-02 by checksum-valid CAS matching. Chemical properties do not replace the regulatory decision on this page.

Records for CAS 25956-17-6

2 total

Annex

III

Entry

191

CURRY RED

Disodium 6-hydroxy-5-[(2-methoxy-4-sulphonato-m-tolyl)azo]naphthalene-2-sulphonate (15); CI 16035. (see note 17)

Hair dye substance in non-oxidative hair dye products

247-368-0

Max concentration

Annex

Entry

CI 16035

Disodium 6-hydroxy-5-[(2-methoxy-4-sulphonato-m-tolyl)azo]naphthalene-2-sulphonate

Purity criteria as set out in Commission Directive 95/45/EC (E 129)

247-368-0

How CAS 25956-17-6 is used on this site

CAS 25956-17-6 is the Chemical Abstracts Service identifier used to pin this page to a specific substance. In the current dataset, 2 EU annex records share this identifier, which helps you cross-check whether the same substance appears under one regulatory context or several.

Use this page when a supplier specification, SDS or raw-material dossier gives you CAS 25956-17-6 and you need to see every linked Annex II–VI record in one place. The entry cards above are the quickest route to concentration limits, warnings, annex placement and product-type conditions.

Frequently asked questions

A substance identified by CAS 25956-17-6 may appear in multiple EU cosmetic regulation annexes when it is subject to different conditions in different contexts. For example, a substance might be restricted under Annex III with specific conditions, and the same CAS might also appear in Annex IV as an approved colorant under separate entry conditions. Each entry must be reviewed individually.

Cross-reference the CAS number against your raw material specification sheets and CoA documents. When a CAS appears in Annex II, verify absence. When it appears in Annex III, verify that concentration limits and product type conditions are met in your formulation. All annex entries sharing this CAS number are listed above.

A CAS number is assigned by the Chemical Abstracts Service (USA) and is globally recognised. An EC number is a European Commission identifier from inventories such as EINECS, ELINCS or the NLP list. Both identifiers may appear in EU cosmetic annex entries. Some substances have both, some have only one, and some older entries may have neither.

The INCI Checker accepts ingredient names, CAS numbers and EC numbers. Check this CAS number directly, then verify the result against supplier specification sheets and every linked annex condition.

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